1. Field of the Invention
The present invention relates to a wet wing. More particularly, it relates to a wet wing having a composite skin utilizing stitches to prevent delamination.
2. Description of the Prior Art
Wet wings of the above mentioned general type are known in the art.
One such wing is disclosed, for example, in a high strain composite skinned wing that utilizes stitches to prevent delamination. The stitches are applied to the wing in a series of substantially mutually perpendicular directions that cross over each other. The final result is a checker board configuration shown in FIG. 1.
When a projectile penetrates a conventional wet wing skin, catastrophic failure of the structure occurs due to the effects of hydrodynamic ram. Hydrodynamic ram causes the impact damage to propagate along the wing skin, which leads to the loss of large sections of the wing skin and ultimate wing failure.
The lines of stitches as taught by the prior art to prevent delamination, have no effect on controlling the damage caused by hydrodynamic ram. cl SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a blow off panel for controlling hydrodynamic ram that avoids the disadvantages of the prior art.
More particularly, it is an object of the present invention to provide a blow off panel for controlling hydrodynamic ram which contains and isolates the damage from the hydrodynamic ram effect to as small an area as possible and thereby prevent catastrophic failure of the structure due to propagation.
In keeping with these objects, and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated, in a wing structure for controlling hydrodynamic ram and which includes a substructure having a plurality of individual cells each of which having a respective boundary, and a composite skin disposed on the substructure wherein first means is disposed through the composite skin and which defines a plurality of sections in the composite skin such that each section of the plurality of sections in the composite skin is disposed within the confines of each respective boundary of each of the plurality of individual cells of the substructure.
When the blow off panel for controlling hydrodynamic ram is designed in accordance with the present invention, each section of the plurality of sections of the composite skin forms a blow off panel for relieving pressure created by hydrodynamic ram in a respective individual cell of the plurality of individual cells of the substructure.
In accordance with another feature of the present invention, the first means includes first perforations along which the blow off panel tears off.
Another feature of the present invention is that it further comprises stitches disposed in the first perforations for arresting the growth of delamination in the composite skin created by impact damage.
Still another feature of the present invention is that the blow off panel has corners at which the stitches touch so that the blow off panel tears off more cleanly and completely.
Yet another feature of the present invention is that the stitches are a composite.
Still another feature of the present invention is that the composite stitches are kevlar/epoxy.
Yet still another feature of the present invention is that the kevlar/epoxy composite stitches and the composite skin are cocured.
Still yet another feature of the present invention is that it further comprise second means disposed in the composite skin for preventing the composite skin from cracking from the first perforations and for preventing the growth of running cracks created by penetration damage.
Another feature of the present invention is that the second means includes a composite.
Yet another feature of the present invention is that the second means composite is fiberglass/epoxy.
Still another feature of the present invention is that it further comprises third means for mounting the composite skin to the substructure.
Yet still another feature of the present invention is that the composite skin contains second perforations for receiving the third means.
Still yet another feature of the present invention is that it further comprises fourth means disposed in the composite skin for preventing the composite skin from cracking from the second perforations.
Another feature of the present invention is that the fourth means includes a composite.
Finally, still a further feature of the present invention is that the fourth means composite is fiberglass/epoxy.
The novel features which are considered characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of the specific embodiment.